Rechargeable batteries are used to power many of today's portable electronic devices. Rechargeable batteries make the portable electronic device more mobile than a device requiring a plug-in power source and this generally adds convenience for the user. However, recharging the batteries for a portable electronic device may be an inconvenience to the user.
For example, a rechargeable battery may carry a limited charge and therefore a user may have to monitor the charge level. Also, a user may have to make arrangements to provide for the charging of the batteries such as by carrying chargers and/or power cords.
Compounding these inconveniences for the user is the potential increased power consumption by modern portable electronic devices. Most portable electronic devices provide more functionality than their predecessors, which usually results in increased power consumption. This means more frequent recharging of the batteries of the portable electronic device, which may result in more recharging inconvenience for the user.
A number of attempts have been made to address recharging for portable electronic devices. For instance, U.S. Pat. No. 6,756,765 to Bruning discloses a system for the contactless recharging of a portable device. The system includes a capacitive plate in a pad onto which the portable device is placed for recharging.
Similarly, U.S. Pat. No. 6,275,681 to Vega et al. discloses a system that includes capacitively coupled capacitor plates for generating an electrostatic field for electrostatic charging of a device like a smart card. The system also includes a charge controller in the rechargeable device for controlling the charging of the battery in the rechargeable device. Another patent to Vega et al. is U.S. Pat. No. 6,282,407, which discloses active and passive electrostatic transceivers that include capacitive charging plates for electrostatically charging. The system also includes an electrostatic reader that continuously generates and transmits an excitation signal to the medium surrounding the reader. In both of the Vega et al. patents, an embodiment is disclosed where a user can manually activate the electrostatic reader instead of having the reader radiating continuously.
Unfortunately for some of the above devices, a user may still need to monitor the charge level of the battery in his portable electronic device. In addition, some of the above devices may require the user to precisely align the electrodes of the charging device with the electrodes in the device being charged. Undesired electromagnetic interference (EMI) may also be generated by capacitive charging arrangements.